scholarly journals Study on Pre Pumping and Outburst Elimination Technology of “one hole and two elimination” in Bedding Directional Long Drilling

2021 ◽  
Vol 329 ◽  
pp. 01089
Author(s):  
Benqing Yuan ◽  
Yongjiang Zhang
Keyword(s):  
Field Test ◽  
Treatment Cycle ◽  
Gas Treatment ◽  
Gas Outburst ◽  
Drainage Time ◽  
Soft Coal ◽  
Working Face ◽  
Reasonable Range ◽  
Gas Control ◽  
Effective Drainage

Aiming at the problem of gas control in the working face and the roadway to be excavated at the same time due to the small construction length of bedding borehole under the condition of the occurrence of soft coal, a technology of "one hole and two elimination" pre-drainage to eliminate gas outburst by using air screw motor drilling was put forward, and the field test was carried out in the 17102(3) working face of Pansu Coal Mine.The results show that this technology can effectively control the borehole trajectory, ensure the uniform and reasonable range of borehole outburst elimination, solve the problems of long gas treatment cycle caused by the construction of gas treatment roadway, improve the effective drainage time of borehole, ensure enough time and space for gas treatment, and be beneficial to the mining and replacement of mine.

Gas Control in Special Soft Coal with Lower Permeability in Liangbei Coal Mine

2012 ◽  
Vol 594-597 ◽  
pp. 2223-2227
Author(s):  
Le Tuan Cheng ◽  
Zheng Sheng Zou ◽  
Qing Bo Li ◽  
Xian Tao Zeng
Keyword(s):  
Coal Mine ◽  
Optimization Technique ◽  
Mining Area ◽  
Gas Pressure ◽  
Gas Content ◽  
Gas Outburst ◽  
Soft Coal ◽  
Efficiency Increase ◽  
Lower Permeability ◽  
Gas Control

Coal seam B1 has characteristics of soft, poor air permeability, high gas content and gas pressure, therefore, there's strong outburst danger in Liangbei Coal Mine. However, the gas control in the coal with lower strength and lower permeability is still in the exploration. Depth of coal roadway is 610-750m at 11 mining area. The roadway excavating speed is seriously influenced by gas outburst, so it brings unfavorable influence to the mine. Based on the principle of relieving gas pressure in the low permeability reservoir, the shortages of existing methods are analyzed for gas control and optimization measure for gas outburst prevention, i.e. "short, flat, long, subtraction, stay, support", put forward from the view of system engineering. With the new measure, drilling efficiency increase, borehole collapse decrease, single borehole drainage scope increase, the gas control meets the requirement and the coal side is easily to be controlled. After application of the optimization technique, the roadway excavating speed is increased from 45m to 70m every month in 11mining area, and the tight situation of excavation replacement is alleviated.

The Adaptation Analysis of the Fully Mechanized Coal Mining Face of Huopu Mine’s Third Soft Coal Seam

2014 ◽  
Vol 1049-1050 ◽  
pp. 335-338 ◽  
Author(s):  
Fa Quan Liu ◽  
Xue Wen Geng ◽  
Yong Che ◽  
Xiang Cui
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Geological Condition ◽  
Soft Coal ◽  
Working Face ◽  
Mining Face ◽  
Soft Coal Seam ◽  
Working Resistance

To get the maximum coal in front of the working face of the 17# coal seam, we installed a longer beam which is 1.2m in length in the leading end of the original working face supports ZF3000/17/28, and know that working face supports’ setting load and working resistance are lower .We changed the original supports with shield supports ZY3800/15/33 that are adaptable in the geological condition and got the favorable affection.

scholarly journals Guiding Effect of Soft Tectonic Coal on Coal and Gas Outburst and its Experimental Study

2021 ◽  
Author(s):  
Qingyi Tu ◽  
Sheng Xue ◽  
Yuanping Cheng ◽  
Wei Zhang ◽  
Gaofeng Shi ◽  
...  
Keyword(s):  
Physical Simulation ◽  
Local Existence ◽  
Coal Pillar ◽  
Gas Pressure ◽  
Coal And Gas Outburst ◽  
Control Group ◽  
Long Distance ◽  
Gas Outburst ◽  
Soft Coal ◽  
Tectonic Coal

Abstract Soft tectonic coal commonly exists in coal and gas outburst zones. The physical simulation experiment was carried out to reproduce the influences of soft coal area on the outburst, and the guiding action mechanism of soft tectonic coal on the outburst was investigated. This study concludes that the amount of outburst coal in the experiments of group with local existence of soft coal area are relatively lower. The outburst coal amount (3.8035 kg) and relative outburst intensity (21.02%) in the GR5# experiment were both lower than that in the GN6# experiment of control group. However, the outburst coal in the experiments of group with local existence of soft coal area could be commonly migrated to a long distance, the maximum throwing distances in the three experiments were all over 16.73 m, reaching as high as 20.10 m. Under the gas pressure of 0.30 MPa in the group with local existence of soft coal area, the outburst coal amount (2.7355 kg) was smaller than the amount (2.803 kg) of pulverized coal filled, and the 2.0 cm coal pillar experiences failure only nearby the outburst mouth. As the gas pressure increases, the failure degree of the coal pillar becomes higher and higher until complete failure. The outburst development sequence is changed due to the existence of the soft tectonic soft area. Once the sealing conditions are destructed, the outburst firstly develops in the soft tectonic coal area. Nevertheless, sufficient energy is supplied to transport the coal mass in the soft tectonic coal area to a farther distance, while the residual outburst energy can just result in the outburst of a small quantity of coal masses in the normal area. This research will be of great scientific significance for explaining the soft tectonic coal-induced change of outburst starting and development sequence.

scholarly journals Research on Control of Rib Spalling Disaster in the Three-Soft Coal Seam

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Feng Cui ◽  
Tinghui Zhang ◽  
Xiaoqiang Cheng
Keyword(s):  
Coal Seam ◽  
Field Experiments ◽  
Simulation Experiment ◽  
Current Status ◽  
Soft Coal ◽  
Grouting Pressure ◽  
Working Face ◽  
Coal Wall ◽  
Soft Coal Seam ◽  
Seam Mining

Rib spalling disaster at the coal mining faces severely restricted the safe and efficient output of coal resources. In order to solve this problem, based on the analysis of the current status of rib spalling in the three-soft coal seam 1508 Working Face of Heyang Coal Mine, a mechanical model of sliding-type rib spalling was established and the main influencing factors that affect rib spalling are given. The mechanism of grouting technology to prevent and control rib spalling has been theoretically analyzed. A similarity simulation experiment is used to analyze the change law of roof stress under the condition of three-soft coal seam mining. The optimal grouting pressure is determined by a numerical simulation experiment. And, silicate-modified polymer grouting reinforcement materials (SMPGMs) are used in field experiments. After twice grouting operations in the 1508 Working Face, the coal wall was changed from the original soft and extremely easy rib spalling to a straight coal wall and the amount of rib spalling has been reduced by 57.45% and 48.43, respectively. And, the mining height has increased by 0.16 m and 0.23 m, respectively. The experimental results show that the rib spalling disaster of the three-soft coal seam has been effectively controlled.

Coal and gas outburst mechanism of the “Three Soft” coal seam in western Henan

2010 ◽  
Vol 20 (5) ◽  
pp. 712-717 ◽  
Author(s):  
Dongji LEI ◽  
Chengwu LI ◽  
Zimin ZHANG ◽  
Yugui ZHANG
Keyword(s):  
Coal Seam ◽  
Coal And Gas Outburst ◽  
Gas Outburst ◽  
Soft Coal ◽  
Soft Coal Seam

scholarly journals Experimental Development of Coal-Like Material with Solid-Gas Coupling for Quantitative Simulation Tests of Coal and Gas Outburst Occurred in Soft Coal Seams

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 155 ◽  
Author(s):  
Xingkai Wang ◽  
Wenbing Xie ◽  
Zhili Su ◽  
Qingteng Tang
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Influencing Factors ◽  
Co2 Sequestration ◽  
Range Analysis ◽  
Coal Seams ◽  
Gas Outburst ◽  
Soft Coal ◽  
Coal Powder ◽  
Adsorption Desorption

Solid-gas coupling coal-like materials are essential for simulating coal and gas outbursts and the long-term safety study of CO2 sequestration in coal. However, reported materials still differ substantially from natural coal in mechanical, deformation and gaseous properties; the latter two aspects are common not considered. There is a lack of a definite and quantitative preparation method of coal-like materials with high similarity for future reference. Here, 25 groups of raw material ratios were designed in the orthogonal experiment using uniaxial compression, shearing and adsorption/desorption tests. Experiment results indicated that the coal-like materials were highly similar to soft coals in properties mentioned above. And range analysis revealed the key influencing factors of each mechanical index. The gypsum/petrolatum ratio controls the density, compressive strength, elastic modulus, cohesion and deformation characteristic. The coarse/fine coal powder (1–2 and 0–0.5 mm) controls the internal friction angle and is the secondary controlling factor for compressive strength and elastic modulus. The effect of coal particle size on the sample strength was studied using scanning electron microscope (SEM). When the gypsum/petrolatum ratio increased, the deformation characteristics changed from ductile to brittle. The different failure modes in the samples were revealed. The coal powder content is a key in the gas adsorption/desorption properties and an empirical formula for estimating the adsorption capacity was established. Based on the range analysis of experimental results, a multiple linear regression model of the mechanical parameters and their key influencing factors was obtained. Finally, a composition closely resembling the natural coal was determined, which differs by only 0.47–7.41% in all parameters except porosity (11.76%). Possible improvements and extension to similar materials are discussed. The findings of this study can help for better understanding of coal and gas outburst mechanism and stability of CO2 sequestration in soft coal seams.

scholarly journals Deviatoric Stress Evolution Laws and Control in Surrounding Rock of Soft Coal and Soft Roof Roadway under Intense Mining Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Dongdong Chen ◽  
Chunwei Ji ◽  
Shengrong Xie ◽  
En Wang ◽  
Fulian He ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Plastic Zone ◽  
Theoretical Calculations ◽  
Coal Pillar ◽  
Surrounding Rock ◽  
Deviatoric Stress ◽  
Anchor Cable ◽  
Soft Coal ◽  
Working Face ◽  
Failure Line

Aiming at the problem of large deformation and instability failure and its control of soft coal and soft roof roadway under intense mining, laboratory experiments, theoretical calculations, Flac3D numerical simulation, borehole peeping, and pressure observation were used to study the deflection characteristics of the deviatoric stress of the gas tailgate and the distribution and failure characteristics of the plastic zone in the mining face considering the strain softening characteristics of the roof and coal of roadway, and then the truss anchor cable-control technology is proposed. The results show the following: (1) The intense mining influence on the working face will deflect the peak deviatoric stress zone (PDSZ) of the surrounding rock of the gas tailgate. The influence distance of PDSZ is about 20 m in advance and 60 m in lag; the PDSZ at the gob side of the roadway is located in the range of 3–5.5 m from the surface of the coal pillar, while the coal wall side is mainly located in the range of 3–4.5 m at the shoulder corner and bottom corner of the solid coal. (2) The intense mining in the working face caused the nonuniform expansion of the surrounding rock plastic area of the gas tailgate. The two shoulder angles of the roadway and the bottom of the coal pillar have the largest damage range, and the maximum damage location is the side angle of the coal pillar (5 m). Angle and bottom angle of coal pillar are the key points of support control. (3) The plastic failure line of the surrounding rock of the gas tailgate is always between the inner and outer contours of the PDSZ, and the rock mass in the PDSZ is in a stable and unstable transition state, so the range of anchor cable support should be cross plastic failure line. (4) The theoretical calculations and numerical simulation results agree well with the drilling peep results. Based on the deflection law of the PDSZ and the expansion characteristics of the plastic zone, a truss anchor cable supporting system with integrated locking and large-scale support function is proposed to jointly control the roof and the two sides, which effectively solves the problem of weak surrounding rock roadway under severe mining deformation control problems realizing safety and efficient production in coal mines under intense mining.

Distribution pattern of front abutment pressure of fully-mechanized working face of soft coal isolated island

2012 ◽  
Vol 22 (2) ◽  
pp. 279-284 ◽  
Author(s):  
Wenquan Xu ◽  
Enyuan Wang ◽  
Rongxi Shen ◽  
Dazhao Song ◽  
Jingmin Zhang
Keyword(s):  
Distribution Pattern ◽  
Abutment Pressure ◽  
Soft Coal ◽  
Working Face

Reasons and Control Countermeasures of Special Soft Coal Roadway Deformation in Liangbei Coal Mine

2013 ◽  
Vol 671-674 ◽  
pp. 1144-1149
Author(s):  
Le Tuan Cheng ◽  
Jia Lin Zhang ◽  
Zheng Sheng Zou ◽  
Qing Bo Li
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Mining Area ◽  
Gas Content ◽  
Deformation And Failure ◽  
Gas Outburst ◽  
Soft Coal ◽  
Coal Roadway ◽  
Roadway Stability ◽  
Roadway Deformation

B1 coal seam located at -550m level in Liangbei Coal Mine is a typical "three-soft" seam. The coal roadway with a depth of 610-750m lies under the critical softening depth of the roadway, and its support difficulty coefficient is 1.5-2.0. The coal has poor air permeability, high gas content and high gas pressure, so danger degree of the gas outburst is relatively strong. The coal seam was destroyed in a disastrous state by more than 100 boreholes for gas outburst prevention during the excavation. This results in the difficulty in the roadway support. Engineering geological characteristics of the coal roadway at 11 mining area are introduced. Based on the engineering geo-mechanics method, the reasons of deformation and failure of the coal roadway are analyzed. In view of problems in excavation and support, as well as the type of the coal roadway deformation mechanism, the borehole parameters are optimized for the gas outburst prevention, and bolt-net-cable coupling support with high convex steel-belt is used to control the coal roadway stability at 11 mining area. Practice shows that the effect is fine.

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